DE102017107821A1 - ARRANGEMENT WITH AT LEAST TWO LASER DIODES AND DIFFACTIVE ELEMENT - Google Patents

Abstract

An arrangement with at least two laser diodes (2, 3, 4) is described, wherein the laser diodes (2, 3, 4) in each case via a side surface (6) electromagnetic radiation (8, 9, 10) in each of a radiation direction (13, 14, 15), wherein the laser diodes (2, 3, 4) are arranged in such a way that the emission directions (13, 14, 15) are arranged substantially parallel, wherein in the emission direction in front of the laser diodes (2, 3, 4) a collecting lens (11) is provided, wherein in the emission direction (13, 14, 15) in front of the converging lens (11) a diffractive optical element (12) is provided, wherein the collecting lens (11) the radiation (8, 9, 10) of the laser diodes (2, 3, 4) on the diffractive optical element (12) collimated.

Description

The invention relates to an arrangement according to claim 1 and a method for controlling the arrangement according to claim 13.

Out DE 10 2013 108 824 A1 a device with a light source and a diffractive optical element is known to perform a beam splitting or widening of the beam of the light source. The light source may be in the form of a laser diode.

The object of the invention is to provide an improved arrangement for providing a radiation source and an improved method for operating the arrangement.

The objects of the invention are solved by the independent claims.

An advantage of the described arrangement is to achieve greater flexibility in providing electromagnetic radiation. This is achieved by providing an arrangement comprising at least two laser diodes. The laser diodes emit electromagnetic radiation in each case in one emission direction. The emission directions are arranged substantially parallel. In the emission direction in front of the laser diodes, a converging lens is provided. The condenser lens is designed to direct the electromagnetic beams of the laser diodes onto a diffractive optical element. The diffractive optical element is configured to scatter the electromagnetic beams of the laser diodes at a plurality of points. Due to the two laser diodes, a higher power of an electromagnetic radiation can be emitted to the diffractive optical element. In addition, different wavelength spectra of electromagnetic radiation can be emitted to the diffractive optical element using the two laser diodes. Furthermore, depending on the selected embodiment, the laser diodes can be operated simultaneously or at different times. Due to the laterally offset arrangement of the laser diodes, that is, the laterally offset emission directions of the electromagnetic radiation of the laser diodes and the subsequent collimation of the electromagnetic radiation by the converging lens, the scattering points of the diffractive optical element are irradiated by the laser diodes at different angles. In this way, an improved provision of a distributed by means of the diffractive optical element electromagnetic radiation can be achieved.

For example, the arrangement can be used to irradiate an object which is arranged after the diffractive optical element, and to detect by means of a sensor, for example, a position, an orientation or a gesture. Thus, the arrangement can be used in particular in a gesture control.

In a further embodiment, the arrangement has a third laser diode. The provision of the third laser diode has the advantage that the electromagnetic radiation power can be increased. In addition, a third scattered light is generated by means of the diffractive optical element and the third laser diode. This achieves a further increase of the scattering points.

In one embodiment, the laser diodes are formed as edge-emitting laser diodes. As a result, a precise alignment and a compact arrangement of the laser diodes can be achieved.

In one embodiment, the lens is configured to direct the electromagnetic beams of the laser diodes to the diffractive optical element at different angles. In this way, the number of illuminated scattering points in the diffractive optical element can be increased, and preferably at the same time the luminance per scattering point is maintained. As a result, the punctual thermal load can be limited.

Depending on the chosen embodiment, the laser diodes are configured to emit electromagnetic radiation having at least partially different wavelengths. In this way, an optimized adaptation of the beam spectrum to the given measurement situation can take place.

In one embodiment, the laser diodes are mounted on a common carrier. As a result, a compact structure of the arrangement can be achieved.

In another embodiment, the laser diodes are monolithically formed as a component with a common substrate. This allows a further reduction of the component. In addition, the alignment and adjustment of the laser diodes in the monolithic structure can be made more precise. In a further embodiment, the laser diodes are arranged side by side and each have a web. Furthermore, the laser diodes are preferably designed to amplify a mode. The arrangement can thus represent a multi-ridge array with singlemode laser diodes.

The angle at which the beams of the laser diodes impinge on the diffractive optical element, depends, for example, on the lateral spacing of the laser diodes and a focal length of a converging lens.

In a further embodiment, a control circuit is provided, wherein the control circuit is designed to control the laser diodes independently of one another. For example, the control circuit may drive the laser diodes in a time-division multiplexing process. In addition, depending on the selected embodiment, the control circuit may be configured to operate the laser diodes in a first operating mode with a lesser number than in a second operating mode. The first mode of operation may be near range short range operation and the second mode of operation may be remote mode for longer ranges of gesture recognition. In this way, a power adjustment of the emitted electromagnetic radiation to the measurement situation can take place.

In a further embodiment, the proposed arrangement is part of a gesture recognition device. With the aid of the device, electromagnetic radiation can be provided as measuring radiation for gesture recognition.

• 1 in einer schematischen Darstellung eine Vorrichtung mit Laserdioden, Sammellinse und einem diffraktivem optischen Element,
• 2 drei Streumuster der drei Laserdioden an dem diffraktiven optischen Element,
• 3 eine schematische perspektivische Darstellung eines Bauteils mit drei Laserdioden.

The above-described characteristics, features, and advantages of this invention, as well as the manner in which they will be achieved, will become clearer and more clearly understood in connection with the following description of the embodiments, which will be described in connection with the drawings. Show it

• 1 in a schematic representation of a device with laser diodes, converging lens and a diffractive optical element,
• 2 three scattering patterns of the three laser diodes on the diffractive optical element,
• 3 a schematic perspective view of a component with three laser diodes.

1 shows a schematic representation of an arrangement with a component 1 , the three laser diodes 2 . 3 . 4 having. The laser diodes 2 . 3 . 4 are shown schematically in the form of strips. Every laser diode 2 . 3 . 4 is designed to generate electromagnetic radiation 8th . 9 . 10 over a first side surface 6 leave. The first side surfaces 6 the laser diodes 2 . 3 . 4 are approximately parallel, in particular aligned parallel to each other. The laser diodes 2 . 3 . 4 thus give the generated electromagnetic radiation 8th . 9 . 10 essentially in parallel radiation directions 13 . 14 . 15 from. Every radiation 8th . 9 . 10 has a predetermined opening angle. The laser diodes 2 . 3 . 4 are adapted to receive electromagnetic radiation between the first side surface 6 and an opposite second side surface 7 train. The first side surface 6 is designed to decouple electromagnetic radiation. The second side surface 7 is designed to be in the laser diode 2 . 3 . 4 reflected electromagnetic radiation. This can, for example, the second side surface 7 be provided with a mirror layer. The laser diodes 2 . 3 . 4 For example, they are designed as semiconductor laser diodes and have corresponding semiconductor layers with an active zone. The active zone is formed, for example, by an interface between a positively doped semiconductor layer and a negatively doped semiconductor layer. The active zone is designed to generate electromagnetic radiation. For example, the laser diodes may be formed as singlemode laser diodes and, for example, have a power in the range of 200 mW. The illustrated laser diodes are designed as edge-emitting laser diodes. Depending on the embodiment chosen, other types of laser diodes may be used to generate three electromagnetic radiations 8th . 9 . 10 to create. In addition, less than three or more than three laser diodes 8th . 9 . 10 be provided.

In the direction of radiation 13 . 14 . 15 is in front of the laser diodes 2 . 3 . 4 a condenser lens 11 intended. The condenser lens 11 is trained to the radiations 8th . 9 . 10 the laser diodes 2 . 3 . 4 on a diffractive optical element 12 to collapse. Because the radiations 8th . 9 . 10 the laser diodes 2 . 3 . 4 are arranged offset laterally, the radiation through the converging lens 11 with different angles of incidence on the diffractive optical element 12 directed. In the illustrated embodiment, the condenser lens 11 trained to the second radiation 9 with a second angle of incidence 32 to collimate to a Einstrahlebene of the diffractive element. The second angle of incidence 32 has 90 ° to the Einstrahlebene of the diffractive optical element 12 on. The first radiation 8th is from the condenser lens 11 with a first angle of incidence 31 less than 90 ° to the irradiation plane of the diffractive optical element 12 directed. Likewise, the third radiation 10 from the condenser lens 11 with a third angle of incidence 33 greater than 90 ° to the Einstrahlebene of the diffractive optical element 12 directed. The first and the third angle of incidence 31 . 33 the first and the third radiation 8th . 10 can each have the same difference angle from the second angle of incidence 32 exhibit. The irradiation plane of the diffractive optical element 12 is in this example parallel to the first side surface 6 of the component 1 arranged. The radiation directions 13 . 14 . 15 are preferably parallel to each other and preferably perpendicular to the first side surface 6 of the component 1 arranged.

The diffractive optical element 12 has a variety of scattering points. With the help of Scattering points become the electromagnetic radiation 8th . 9 . 10 the laser diodes 2 . 3 . 4 scattered in a variety of beam directions.

Due to the different irradiation angles of the radiations 2 . 3 . 4 Preferably, different scattering points of the diffractive optical element are irradiated by the three radiations. In this way, a reduction of the radiation load of the individual scattering points can be achieved, wherein the radiant power that impinges on the diffractive optical element as a whole can remain the same size. In addition, an improved widening and scattering of the electromagnetic radiation can be achieved by the different angles of incidence.

The component 1 is trained to the laser diodes 2 . 3 . 4 to operate independently of each other. For this purpose, at least one electrical connection of the laser diodes is formed separately from the electrical connections of the other laser diodes.

The laser diodes 2 . 3 . 4 may be formed as separate laser diodes and be mounted on a common carrier and the component 1 represent. Depending on the selected embodiment, the laser diodes may also be formed monolithically as a component with a common substrate.

It is a control circuit 16 provided, via corresponding electrical control lines to the electrical terminals of the laser diodes 2 . 3 . 4 connected is. For this purpose, the control lines are formed in such a way that the laser diodes 2 . 3 . 4 can also be controlled independently of each other. The control circuit 16 is designed to drive the laser diodes, for example, simultaneously, with a time offset or only a part of the laser diodes. In particular, the control circuit can be designed to control the laser diodes in a time-division multiplex method. For example, the control circuit 16 be configured to control only a portion of the laser diodes, in particular only one laser diode in a Nahbetrieb example, for a gesture detection. In addition, the control circuit may be designed to control at least two or all three laser diodes in a remote operation, for example for a gesture recognition. Thus, that of the component 1 emitted electromagnetic radiation power can be adapted to the present measurement situation. For gesture recognition, an optical sensor is provided which detects electromagnetic radiation that is emitted by an object in the emission direction after the diffractive optical element 12 is reflected. From the spectrum, the temporal arrival and / or the intensity over the surface of the received reflected electromagnetic radiation, a statement or a recognition of an object or a gesture can take place.

Depending on the chosen embodiment, it may be advantageous if the three laser diodes emit electromagnetic radiation having different wavelength spectra. For example, at least one of the laser diodes, in particular all laser diodes, emit electromagnetic radiation in the infrared range.

2 shows a schematic representation of a first scattering image 17 , which schematically shows the scattering points of the diffractive optical element 12 shows that from the first radiation 8th the first laser diode 2 be illuminated. In addition shows 2 a second spreading pattern 18 that shows the scattering points from the second radiation 9 the second laser diode 3 be illuminated. In addition shows 2 a third spread 19 that the scattering points of the diffractive optical element 12 shows that of the third radiation 10 the third laser diode 4 be illuminated. The diffractive optical element 12 can be trained to look at all three scatter patterns 17 . 18 . 19 to produce a same pattern, which is arranged laterally offset due to the different angles of incidence of the electromagnetic radiation of the laser diodes. Thus, a homogeneous total radiation can be generated after the diffractive optical element, which upon irradiation of the diffractive optical element 12 with the radiations 8th . 9 . 10 the laser diodes 2 . 3 . 4 has a superposition of three identical but laterally offset spreading patterns.

3 shows a schematic representation of a perspective view of an embodiment of a component 1 , In the illustrated embodiment, the component 1 a monolithic structure, wherein three laser diodes 2 . 3 . 4 in the component 1 are integrated. This is on a substrate 20 a semiconductor layer structure having a first and a second layer 21 . 22 arranged. In the illustrated embodiment, the first layer is 21 negatively doped. The second layer 22 is positively endowed. At an interface between the two layers 21 . 22 is an active zone 23 educated. Depending on the chosen embodiment, the active zone 23 also have quantum well structures. On the second layer 22 is each a jetty 24 arranged of an electrically conductive material. The jetty 24 may also be formed of an electrically conductive semiconductor material. The first and the second layer 21 . 22 can be formed as epitaxially deposited layers in particular from the material system aluminum-indium-gallium-nitride. The bridges 24 serve as the first electrical connection, for example 25 , The substrate 20 can out an electrically conductive semiconductor material and, for example, as a second electrical connection 26 serve. Under the bridges 24 is between opposite side surfaces 6 . 7 in the area of the active zone 23 an optical mode formed over a radiating surface 27 . 28 . 29 on the first side surface 6 of the component 1 is emitted.

The component 1 of the 3 For example, it may represent a singlemode laser array in the form of an edge emitter.

Diffractive optical elements (DOE) may e.g. Glass support on which microstructures are applied by photolithography. In them, different optical path lengths of the partial beams lead to phase modulations, which results in interference patterns. In addition, the amplitude is modulated by constructive and destructive superimposition. Thus, by skillful design, the intensity patterns can be manipulated in a laser beam. Diffractive optical elements can be used to shape a laser beam or to break it up into several partial beams. The microstructure in the diffractive optical element can shape the beam by refractive index or by height modulation. Good diffractive optical elements achieve efficiencies of 80-99% and transmittances of 95-99%.

The invention has been further illustrated and described with reference to the preferred embodiments. However, the invention is not limited to the disclosed examples. Rather, other variations may be deduced therefrom by those skilled in the art without departing from the scope of the invention.

LIST OF REFERENCE NUMBERS

1

component

2

first laser diode

3

second laser diode

4

third laser diode

6

first side surface

7

second side surface

8th

first radiation

9

second radiation

10

third radiation

11

converging lens

12

diffractive optical element

13

first emission direction

14

second emission direction

15

third emission direction

16

control circuit

17

first spreading picture

18

second spreading pattern

19

third spreading pattern

20

substratum

21

first shift

22

second layer

23

active zone

24

web

25

first electrical connection

26

second electrical connection

27

first radiating surface

28

second emission surface

29

third emitting surface

31

first angle of incidence

32

second angle of incidence

33

third angle of incidence

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102013108824 A1 [0002]

Claims (15)

Arrangement with at least two laser diodes (2, 3, 4), wherein the laser diodes (2, 3, 4) emit electromagnetic radiation (8, 9, 10) in a respective emission direction (13, 14, 15) via a side surface (6) , wherein the laser diodes (2, 3, 4) are arranged in such a way that the emission directions (13, 14, 15) are arranged substantially parallel, wherein in the emission direction in front of the laser diodes (2, 3, 4) a convergent lens ( 11) is provided, wherein in the emission direction (13, 14, 15) in front of the convergent lens (11) a diffractive optical element (12) is provided, wherein the convergent lens (11) the radiation (8, 9, 10) of the laser diodes ( 2, 3, 4) on the diffractive optical element (12) collimated. Arrangement according to Claim 1 , wherein a third laser diode (4) is provided, wherein the third laser diode (4) via one side electromagnetic radiation (10) emits in a radiation direction (15), wherein the emission direction (15) of the third laser diode (4) substantially parallel to the radiation directions (13, 14, 15) of the first and the second laser diode (2, 3) is arranged, wherein the converging lens (11) collimates the radiation (10) of the third laser diode (4) on the diffractive optical element (12). Arrangement according to Claim 1 or 2 , wherein the laser diodes (2, 3, 4) as edge-emitting laser diodes (2, 3, 4) are formed. Arrangement according to one of the preceding claims, wherein the convergent lens (11) is designed to bring the electromagnetic beams (8, 9, 10) of the laser diodes (2, 3, 4) with different angles of incidence (31, 32, 33) to a radiation plane of the beam to direct diffractive optical element (12). Arrangement according to one of the preceding claims, wherein the laser diodes (2, 3, 4) emit electromagnetic beams (8, 9, 10) with at least partially different wavelengths. Arrangement according to one of the preceding claims, wherein the laser diodes (2, 3, 4) are mounted on a common carrier. Arrangement according to one of the preceding claims, wherein the laser diodes (2, 3, 4) are monolithically formed as a component (1) with a common substrate (20). Arrangement according to one of the preceding claims, wherein the laser diodes (2, 3, 4) are arranged side by side, wherein the laser diodes (2, 3, 4) each have a web (24). Arrangement according to one of the preceding claims, wherein a control circuit (16) is provided, wherein the control circuit (16) is designed to control the laser diodes (2, 3, 4) independently of each other. Arrangement according to Claim 9 , wherein the control circuit (16) is adapted to drive the laser diodes (2, 3, 4) in a time division multiplex method. Arrangement according to one of Claims 9 or 10 in that the control circuit (16) is designed to control fewer laser diodes (2, 3, 4) in a first operating mode than in a second operating mode. Arrangement according to one of the preceding claims, wherein the arrangement is part of a gesture recognition device. Method for operating an arrangement according to one of the preceding claims, wherein depending on a measurement situation, the laser diodes are driven differently. Method according to Claim 13 , wherein in a first operating mode, only a portion of the laser diodes is driven, wherein in a second operating mode, all the laser diodes are driven. Method according to one of Claims 13 or 14 , wherein the arrangement is used as a radiation source for gesture recognition.

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